Enantioconvergent Cross-Couplings of Racemic Alkylmetal Reagents with Unactivated Secondary Alkyl Electrophiles: Catalytic Asymmetric Negishi α-Alkylations of <i>N</i>-Boc-pyrrolidine
作者:Christopher J. Cordier、Rylan J. Lundgren、Gregory C. Fu
DOI:10.1021/ja4054114
日期:2013.7.31
Although enantioconvergent alkyl-alkyl couplings of racemic electrophiles have been developed, there have been no reports of the corresponding reactions of racemic nucleophiles. Herein we describe Negishi cross-couplings of racemic α-zincated N-Boc-pyrrolidine with unactivated secondary halides, thus providing a one-pot, catalytic asymmetric method for the synthesis of a range of 2-alkylpyrrolidines
尽管已经开发了外消旋亲电子试剂的对映异构烷基-烷基偶联,但还没有外消旋亲核试剂的相应反应的报道。在此,我们描述了外消旋 α-锌化 N-Boc-吡咯烷与未活化的仲卤化物的根岸交叉偶联,从而为合成一系列 2-烷基吡咯烷(目标分子的重要家族)提供了一种一锅催化不对称方法。来自 N-Boc-吡咯烷,一种市售前体。初步机制研究表明,两种最直接的对映体聚合机制(有机金属偶联伙伴的动态动力学拆分和简单的 β-氢化物消除/β-迁移插入途径)不太可能起作用。